Advanced Water Management Centre, The University of Queensland, St. Lucia, Queensland 4072, Australia.
Environ Sci Technol. 2013 Jul 16;47(14):7795-803. doi: 10.1021/es4005398. Epub 2013 Jun 27.
Mathematical modeling of N2O emissions is of great importance toward understanding the whole environmental impact of wastewater treatment systems. However, information on modeling of N2O emissions from full-scale wastewater treatment plants (WWTP) is still sparse. In this work, a mathematical model based on currently known or hypothesized metabolic pathways for N2O productions by heterotrophic denitrifiers and ammonia-oxidizing bacteria (AOB) is developed and calibrated to describe the N2O emissions from full-scale WWTPs. The model described well the dynamic ammonium, nitrite, nitrate, dissolved oxygen (DO) and N2O data collected from both an open oxidation ditch (OD) system with surface aerators and a sequencing batch reactor (SBR) system with bubbling aeration. The obtained kinetic parameters for N2O production are found to be reasonable as the 95% confidence regions of the estimates are all small with mean values approximately at the center. The model is further validated with independent data sets collected from the same two WWTPs. This is the first time that mathematical modeling of N2O emissions is conducted successfully for full-scale WWTPs. While clearly showing that the NH2OH related pathways could well explain N2O production and emission in the two full-scale plants studied, the modeling results do not prove the dominance of the NH2OH pathways in these plants, nor rule out the possibility of AOB denitrification being a potentially dominating pathway in other WWTPs that are designed or operated differently.
对污水处理系统的整体环境影响进行了解的关键在于对 N2O 排放的数学模型进行研究。然而，目前对于全规模污水处理厂（WWTP）中 N2O 排放的建模信息仍然很少。在这项工作中，我们开发并校准了一个基于目前已知或假设的异养反硝化菌和氨氧化菌（AOB）产生 N2O 的代谢途径的数学模型，以描述全规模 WWTP 中的 N2O 排放。该模型很好地描述了从具有表面曝气的开放式氧化沟（OD）系统和具有鼓泡曝气的序批式反应器（SBR）系统收集的动态氨、亚硝酸盐、硝酸盐、溶解氧（DO）和 N2O 数据。发现获得的 N2O 产生动力学参数是合理的，因为估计值的 95%置信区间都很小，平均值大致在中心。该模型还使用来自同一两个 WWTP 的独立数据集进行了验证。这是首次成功地对全规模 WWTP 中的 N2O 排放进行数学建模。虽然模型的结果清楚地表明，NH2OH 相关途径可以很好地解释所研究的两个全规模工厂中 N2O 的产生和排放，但这些建模结果并不能证明 NH2OH 途径在这些工厂中的主导地位，也不能排除在其他设计或运行方式不同的 WWTP 中，AOB 反硝化可能是一种潜在的主导途径的可能性。
